<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>optgroup>标签分组</title>
	</head>
	<body>
		<form action="form.php" method="post"> 
		 <select name="city"> 
		 <optgroup label="山东省"> 
		 <option value="1" title="青岛">青岛</option> 
		 <option value="2" selected="selected">烟台</option> 
		 <option value="3">济南</option> 
		 </optgroup> 
		 <optgroup label="北京市"> 
		 <option>海淀区</option> 
		 <option>朝阳区</option> 
		 </optgroup> 
		</select> 
		</form> 
	</body>
</html>